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<div class="titlepage"><div><div><h4 class="title">
<a name="boost_asio.reference.spawn.overload1"></a><a class="link" href="overload1.html" title="spawn (1 of 6 overloads)">spawn (1 of 6
        overloads)</a>
</h4></div></div></div>
<p>
          Start a new stackful coroutine that executes on a given executor.
        </p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
    <span class="keyword">typename</span> <a class="link" href="../Executor1.html" title="Executor requirements">Executor</a><span class="special">,</span>
    <span class="keyword">typename</span> <span class="identifier">F</span><span class="special">,</span>
    <span class="keyword">typename</span> <span class="identifier">CompletionToken</span> <span class="special">=</span> <span class="identifier">default_completion_token_t</span><span class="special">&lt;</span><span class="identifier">Executor</span><span class="special">&gt;&gt;</span>
<span class="keyword">auto</span> <span class="identifier">spawn</span><span class="special">(</span>
    <span class="keyword">const</span> <span class="identifier">Executor</span> <span class="special">&amp;</span> <span class="identifier">ex</span><span class="special">,</span>
    <span class="identifier">F</span> <span class="special">&amp;&amp;</span> <span class="identifier">function</span><span class="special">,</span>
    <span class="identifier">CompletionToken</span> <span class="special">&amp;&amp;</span> <span class="identifier">token</span> <span class="special">=</span> <span class="identifier">default_completion_token_t</span><span class="special">&lt;</span> <span class="identifier">Executor</span> <span class="special">&gt;(),</span>
    <span class="identifier">constraint_t</span><span class="special">&lt;</span> <span class="identifier">is_executor</span><span class="special">&lt;</span> <span class="identifier">Executor</span> <span class="special">&gt;::</span><span class="identifier">value</span><span class="special">||</span><span class="identifier">execution</span><span class="special">::</span><span class="identifier">is_executor</span><span class="special">&lt;</span> <span class="identifier">Executor</span> <span class="special">&gt;::</span><span class="identifier">value</span> <span class="special">&gt;</span>  <span class="special">=</span> <span class="number">0</span><span class="special">);</span>
</pre>
<p>
          This function is used to launch a new stackful coroutine.
        </p>
<h6>
<a name="boost_asio.reference.spawn.overload1.h0"></a>
          <span class="phrase"><a name="boost_asio.reference.spawn.overload1.parameters"></a></span><a class="link" href="overload1.html#boost_asio.reference.spawn.overload1.parameters">Parameters</a>
        </h6>
<div class="variablelist">
<p class="title"><b></b></p>
<dl class="variablelist">
<dt><span class="term">ex</span></dt>
<dd><p>
                Identifies the executor that will run the stackful coroutine.
              </p></dd>
<dt><span class="term">function</span></dt>
<dd>
<p>
                The coroutine function. The function must be callable the signature:
              </p>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">function</span><span class="special">(</span><span class="identifier">basic_yield_context</span><span class="special">&lt;</span><span class="identifier">Executor</span><span class="special">&gt;</span> <span class="identifier">yield</span><span class="special">);</span>
</pre>
</dd>
<dt><span class="term">token</span></dt>
<dd><p>
                The <a class="link" href="../../overview/model/completion_tokens.html" title="Completion Tokens">completion
                token</a> that will handle the notification that the coroutine
                has completed. If the return type <code class="computeroutput"><span class="identifier">R</span></code>
                of <code class="computeroutput"><span class="identifier">function</span></code> is <code class="computeroutput"><span class="keyword">void</span></code>, the function signature of the
                completion handler must be:
              </p></dd>
</dl>
</div>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">exception_ptr</span><span class="special">);</span>
</pre>
<p>
          Otherwise, the function signature of the completion handler must be:
        </p>
<pre class="programlisting"><span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">exception_ptr</span><span class="special">,</span> <span class="identifier">R</span><span class="special">);</span>
</pre>
<h6>
<a name="boost_asio.reference.spawn.overload1.h1"></a>
          <span class="phrase"><a name="boost_asio.reference.spawn.overload1.completion_signature"></a></span><a class="link" href="overload1.html#boost_asio.reference.spawn.overload1.completion_signature">Completion
          Signature</a>
        </h6>
<pre class="programlisting"><span class="keyword">void</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">exception_ptr</span><span class="special">,</span> <span class="identifier">R</span><span class="special">)</span>
</pre>
<p>
          where <code class="computeroutput"><span class="identifier">R</span></code> is the return type
          of the function object.
        </p>
<h6>
<a name="boost_asio.reference.spawn.overload1.h2"></a>
          <span class="phrase"><a name="boost_asio.reference.spawn.overload1.per_operation_cancellation"></a></span><a class="link" href="overload1.html#boost_asio.reference.spawn.overload1.per_operation_cancellation">Per-Operation
          Cancellation</a>
        </h6>
<p>
          The new thread of execution is created with a cancellation state that supports
          <code class="computeroutput"><span class="identifier">cancellation_type</span><span class="special">::</span><span class="identifier">terminal</span></code> values only. To change the cancellation
          state, call the <a class="link" href="../basic_yield_context.html" title="basic_yield_context"><code class="computeroutput"><span class="identifier">basic_yield_context</span></code></a> member function
          <code class="computeroutput"><span class="identifier">reset_cancellation_state</span></code>.
        </p>
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<div class="copyright-footer">Copyright © 2003-2025 Christopher M.
      Kohlhoff<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
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